// download.js v4.2, by dandavis; 2008-2016. [CCBY2] see http://danml.com/download.html for tests/usage
// v1 landed a FF+Chrome compat way of downloading strings to local un-named files, upgraded to use a hidden frame and optional mime
// v2 added named files via a[download], msSaveBlob, IE (10+) support, and window.URL support for larger+faster saves than dataURLs
// v3 added dataURL and Blob Input, bind-toggle arity, and legacy dataURL fallback was improved with force-download mime and base64 support. 3.1 improved safari handling.
// v4 adds AMD/UMD, commonJS, and plain browser support
// v4.1 adds url download capability via solo URL argument (same domain/CORS only)
// v4.2 adds semantic variable names, long (over 2MB) dataURL support, and hidden by default temp anchors
// https://github.com/rndme/download

(function (root, factory) {
  if (typeof define === 'function' && define.amd) {
    // AMD. Register as an anonymous module.
    define([], factory);
  } else if (typeof exports === 'object') {
    // Node. Does not work with strict CommonJS, but
    // only CommonJS-like environments that support module.exports,
    // like Node.
    module.exports = factory();
  } else {
    // Browser globals (root is window)
    root.download = factory();
  }
}(this, () => function download(data, strFileName, strMimeType) {

  let self = window; // this script is only for browsers anyway...
  let defaultMime = 'application/octet-stream'; // this default mime also triggers iframe downloads
  let mimeType = strMimeType || defaultMime;
  let payload = data;
  let url = !strFileName && !strMimeType && payload;
  let anchor = document.createElement('a');
  let toString = function (a) { return String(a); };
  let myBlob = (self.Blob || self.MozBlob || self.WebKitBlob || toString);
  let fileName = strFileName || 'download';
  let blob;
  let reader;
  myBlob = myBlob.call ? myBlob.bind(self) : Blob;

  if (String(this) === 'true') { // reverse arguments, allowing download.bind(true, "text/xml", "export.xml") to act as a callback
    payload = [payload, mimeType];
    mimeType = payload[0];
    payload = payload[1];
  }


  if (url && url.length < 2048) { // if no filename and no mime, assume a url was passed as the only argument
    fileName = url.split('/').pop().split('?')[0];
    anchor.href = url; // assign href prop to temp anchor
    if (anchor.href.indexOf(url) !== -1) { // if the browser determines that it's a potentially valid url path:
      let ajax = new XMLHttpRequest();
      ajax.open('GET', url, true);
      ajax.responseType = 'blob';
      ajax.onload = function (e) {
        download(e.target.response, fileName, defaultMime);
      };
      setTimeout(() => { ajax.send(); }, 0); // allows setting custom ajax headers using the return:
      return ajax;
    } // end if valid url?
  } // end if url?


  // go ahead and download dataURLs right away
  if (/^data\:[\w+\-]+\/[\w+\-]+[,;]/.test(payload)) {

    if (payload.length > (1024 * 1024 * 1.999) && myBlob !== toString) {
      payload = dataUrlToBlob(payload);
      mimeType = payload.type || defaultMime;
    } else {
      return navigator.msSaveBlob // IE10 can't do a[download], only Blobs:
        ? navigator.msSaveBlob(dataUrlToBlob(payload), fileName)
        : saver(payload); // everyone else can save dataURLs un-processed
    }

  }// end if dataURL passed?

  blob = payload instanceof myBlob
    ? payload
    : new myBlob([payload], { type: mimeType });


  function dataUrlToBlob(strUrl) {
    let parts = strUrl.split(/[:;,]/);
    let type = parts[1];
    let decoder = parts[2] == 'base64' ? atob : decodeURIComponent;
    let binData = decoder(parts.pop());
    let mx = binData.length;
    let i = 0;
    let uiArr = new Uint8Array(mx);

    for (i; i < mx; ++i) uiArr[i] = binData.charCodeAt(i);

    return new myBlob([uiArr], { type });
  }

  function saver(url, winMode) {

    if ('download' in anchor) { // html5 A[download]
      anchor.href = url;
      anchor.setAttribute('download', fileName);
      anchor.className = 'download-js-link';
      anchor.innerHTML = 'downloading...';
      anchor.style.display = 'none';
      document.body.appendChild(anchor);
      setTimeout(() => {
        anchor.click();
        document.body.removeChild(anchor);
        if (winMode === true) { setTimeout(() => { self.URL.revokeObjectURL(anchor.href); }, 250); }
      }, 66);
      return true;
    }

    // handle non-a[download] safari as best we can:
    if (/(Version)\/(\d+)\.(\d+)(?:\.(\d+))?.*Safari\//.test(navigator.userAgent)) {
      url = url.replace(/^data:([\w\/\-\+]+)/, defaultMime);
      if (!window.open(url)) { // popup blocked, offer direct download:
        if (confirm('Displaying New Document\n\nUse Save As... to download, then click back to return to this page.')) { location.href = url; }
      }
      return true;
    }

    // do iframe dataURL download (old ch+FF):
    let f = document.createElement('iframe');
    document.body.appendChild(f);

    if (!winMode) { // force a mime that will download:
      url = `data:${url.replace(/^data:([\w\/\-\+]+)/, defaultMime)}`;
    }
    f.src = url;
    setTimeout(() => { document.body.removeChild(f); }, 333);

  }// end saver


  if (navigator.msSaveBlob) { // IE10+ : (has Blob, but not a[download] or URL)
    return navigator.msSaveBlob(blob, fileName);
  }

  if (self.URL) { // simple fast and modern way using Blob and URL:
    saver(self.URL.createObjectURL(blob), true);
  } else {
    // handle non-Blob()+non-URL browsers:
    if (typeof blob === 'string' || blob.constructor === toString) {
      try {
        return saver(`data:${mimeType};base64,${self.btoa(blob)}`);
      } catch (y) {
        return saver(`data:${mimeType},${encodeURIComponent(blob)}`);
      }
    }

    // Blob but not URL support:
    reader = new FileReader();
    reader.onload = function (e) {
      saver(this.result);
    };
    reader.readAsDataURL(blob);
  }
  return true;
} /* end download() */));
